1. Field of the Invention
The present invention relates to an optical indicator element, which receives light from at least one light source.
2. Description of the Background Art
Symbols on control or operating elements, for example in a motor vehicle, are illuminated or back-lighted by light sources for better recognizability and differentiation, especially in case of night driving. It is known that one requirement in the illumination of such operating elements is illuminating the symbols uniformly for night-and-day design.
In practice, both the locator and function symbols are illuminated separately from one another for this purpose. Depending on the size of the operating element, it is illuminated directly or through a light conductor system. For illuminating the function symbol, for example, a light conductor is led into the knob area and the light from a light source is coupled into the function symbol. The locator symbol is illuminated by lateral coupling of the light through another light conductor.
DE 198 40 070 A1, DE 197 38 666 C1, and DE 198 53 819 A1 describe such backlighted operating elements. The last-mentioned patent in particular discloses search lighting or function lighting, wherein in one embodiment it is proposed to make a cap for the switch out of transparent material that is painted in a color of the symbol in a first operating step. In a second operating step, the final surface color of the cap is then applied. To expose the color of the symbol, the color of the surface is then removed with a laser so that the symbol is depicted in its precise shape.
A method and a system for adjusting the brightness of a light can be found in DE 196 02 891 A1. After manufacturing an indicator, a correction factor is determined as a function of the brightness of the light, by adjusting a control voltage or control current of the light to achieve uniform illumination or indicator brightness.